The incorporation of antimicrobial substances in fabrics, paper, and related materials to prevent microbial growth and contamination in the material is well known. U.S. Pat. No. 3,728,213 issued to Charles F. Hinz on Apr. 17, 1973, discloses the incorporation of pseudoureas as antimicrobials in nonwoven fabrics utilized as surgical drapes, hospital gowns, etc.
Antimicrobials that are incorporated into fabrics which are activated when the fabrics are wetted are also known in the art. U.S. Pat. No. 2,883,322 issued to Francis O. Whippel on Apr. 21, 1959, discloses a cellulosic paper laminate with one layer containing an ammonium salt and another layer in contact with the first containing an alkaline compound. When wetted, the ammonium salt and alkaline compound react to form ammonia which acts as an antimicrobial. U.S. Pat. No. 3,152,957 issued to Akira Sakuma et al. on Oct. 13, 1964, also discloses a system in which an antimicrobial precursor is kept in one layer and a base which will activate the antimicrobial precursor is kept in a second layer in contact with the first such that when both are wetted, the antimicrobial will be liberated. U.S. Pat. No. 3,579,628 issued to Robert J. Gander et al. on May 18, 1971, discloses antimicrobial precursors that are incorporated in fabrics which when contacted with water react with the water to form formaldehyde which acts as an antimicrobial.
The use of carboxylates either alone or in conjunction with other substances to inhibit the growth of bacteria, fungi and molds in a variety of products is well known. For example, sodium propionate is routinely added to commercial bread to inhibit mold. The Merck Index, Seventh Edition, page 1117, teaches that zinc propionate is used as a fungicide on adhesive tape to reduce plaster irritation caused by molds, fungi and bacteria action.
U.S. Pat. No. 1,772,975 issued to Herman Wieland on Aug. 12, 1930, teaches the use of solutions of lactic acid, acetic acid, or homologues thereof, as antiseptics at properly adjusted pH's. U.S. Pat. No. 2,466,663 issued to Walter R. Russ et al. on Apr. 5, 1949, describes the use of caprylic (octanoic) acid to combat mycotic infection or growths. This substance may be formulated to be used topically as a liquid, ointment or butter in the treatment of surface infections. Russ also discloses that salts of caprylic acid including sodium caprylate may be used in his antifungal products; he prefers that they have a pH between 4.5 and 10.5. U.S. Pat. No. 2,190,714 issued to Charles Hoffman et al. on Feb. 20, 1940, claims a method of inhibiting mold growth in food products other than margarine and sourdough bread by adding a C.sub.3 -C.sub.12 saturated branched or straight chain monocarboxylic aliphatic acid thereto.
U.S. Pat. No. 4,002,775 issued to Jon J. Kabara on January 11, 1977, describes fatty acids and derivatives as antimicrobial agents. According to Kabara, caprylic (octanoic) acid is not inhibitory to any of the microorganisms under the test conditions. However, properly used in the manner disclosed herein, octanoic acid has been found to be a particularly potent antimicrobial agent when incorporated into nonwoven fabrics.
U.S. Pat. No. 2,154,449 issued to Charles Hoffman et al. on April 18, 1939, describes the use of C.sub.3 -C.sub.12 saturated branched or straight chain monocarboxylic aliphatic acids or their salts as mold inhibitors to protect a variety of materials susceptible to mold including foods, tobacco, paper, leather, textiles, etc. U.S. Pat. No. 2,729,586 issued to Samuel M. Peck on Jan. 3, 1956, discloses that C.sub.3 -C.sub.11 monocarboxylic acids are bacteristatic as well as fungistatic. Peck recognizes that many of the monocarboxylic acids have an unpleasant odor and are consequently unsuitable for use in some applications. Peck discloses the use of chlorophyll in combination with monocarboxylic acids to provide an antimicrobial in wet dressings which has an improved odor.
Canadian Pat. No. 553,057 issued to Henry J. Ferlin et al. on Feb. 11, 1958, discloses that C.sub.9 -C.sub.12 saturated aliphatic monocarboxylic acids are powerful bactericides in aqueous solution at a pH below 6 but are much less effective at higher pH's.
Canadian Pat. No. 1,098,039 issued to Roger L. Stone on Mar. 24, 1981 describes intravenous aqueous solutions incorporating C.sub.4 -C.sub.9 n-fatty acid antimicrobials. It is the equivalent of U.S. Application Ser. No. 816,625, filed July 18, 1977, now abandoned, which is a continuation-in-part of Application Ser. No. 709,342, filed July 28, 1976, now abandoned. Co-pending Application Ser. No. 918,532 which is a continuation-in-part of U.S. Application Ser. No. 816,625, is incorporated herein by reference.
Co-pending Application Ser. No. 53,619 of Robert V. Mustacich et al., filed June 29, 1979, which is incorporated herein by reference, discloses carboxylate antimicrobial agents releasably incorporated within a polymer matrix, said polymer also containing a substantially nonantimicrobial proton donor. An equivalent to this application was published as European Patent Office Application No. 0022289 on Jan. 14, 1981.
It is an object of the present invention to incorporate monocarboxylate antimicrobial precursors into nonwoven fabrics and the like such that they exhibit antimicrobial activity upon being wetted.
It is a further object of this invention to produce such antimicrobial treated materials with minimal unpleasant odor.
These and other objects will become apparent from the following detailed description. All percentages herein are by weight unless otherwise specified.